Internal combustion engines are used in a wide variety of applications to power things such as motor boats, power tools, lawn and garden equipment and a wide range of vehicles. As concern for the environment increases government regulations have been and are being promulgated requiring reduced emissions and improved fuel economy from internal combustion engines. One method used to lower the emissions and fuel consumption of internal combustion engines has been the use of fuel injectors as opposed to carburetors to meter and supply fuel to the engine. Electronic fuel injectors can be precisely timed to deliver metered quantities of fuel to the engine at the appropriate times to reduce emissions and fuel consumption and have therefore been widely used. However, electronic and computer monitored fuel injectors add considerable cost and complexity to the system and are impractical for many small engine systems which do not have a battery or generator to power and control the electronic fuel injection systems.
Another approach to lowering the fuel consumption and emission rates of internal combustion engines is to directly inject the fuel into an engine cylinder as opposed to an intake manifold of the engine which permits better timing of the injection to reduce fuel losses in the exhaust scavenge gases thereby reducing hydrocarbon exhaust emissions and decreasing the fuel consumption of the engine. In some present systems, a fuel injector delivers fuel, usually at a relatively low pressure, to a compression chamber wherein the fuel is mixed with air creating a combustionable mixture which is injected directly into the cylinder of the engine. While these systems have been effective at reducing fuel consumption and emissions from the engine they are relatively expensive due to the fuel injector and the overall complexity of the systems and also increase the size of the engine as the compression chamber is located on top of the cylinder head with one fuel injector mounted adjacent to the compression chamber of each cylinder. This is undesirable for small engines such as those in lawn and garden equipment, boat motors and small motorcycle engines and the like where a compact engine is required. Further, as discussed above fuel injectors add complexity and greatly increase the cost of the engine system.